This invention relates to a method of converting a strip of flexible material into a stack of folded members and, more particularly, to a stack having at least one side where all of the folded members are aligned.
The need to convert a strip of flexible material into a stack of folded members arises in many industries, such as the textile and rubber industries. In the rubber industry, one such need arises when processed rubber is to be used in injection molding machines. A method of processing rubber, either synthetic or natural, begins by dumping the necessary raw materials into the hopper of a Banbury. After the raw materials are properly mixed, the resulting rubber is conveyed to a screw feeder which further mixes the rubber and conveys it to a calender. The calender includes a pair of rollers that transform the screw fed rubber into a wide strip of rubber. Generally, this wide strip of rubber has a width of between thirty inches (76.2 cm) and thirty-six inches (91.44 cm). If this rubber is to be used in an injection molding machine, it must be cut into narrow strips. Injection molding machines typically will only accept rubber strips with a width of six inches (15.24 cm) or less. To load these strips into an injection molding machine, an operator feeds an end of a narrow rubber strip into an inlet of the injection molding machine. After accepting the end of the narrow strip of rubber, the injection molding machine automatically draws the strip into the inlet as needed.
To efficiently produce injection molded rubber products, rubber manufacturers need an efficient way to produce these narrow strips of rubber and to transport these strips of rubber to the location of the injection molding machines. Since most manufacturing plants are already equipped to move palletieed products, the easiest way to sport a product from one location to another is to stack the product and transport it on a pallet.
If the product is to be transported by pallet, a rubber manufacturer can either cut the wide strip of rubber into narrow strips prior to palletizing, or they can palletize the wide strip and then cut it into narrow strips. Whichever method is used to reduce the width of the rubber strips, there is a need to neatly stack the rubber. If the rubber is cut into narrow strips prior to stacking, the stacks must be neat to assure that a first narrow strip is not overlapped by a second narrow strip. If the second narrow strip overlaps the first narrow strip, the first narrow strip will likely break when being drawn into the injection molding machine. The overlap of the second narrow strip applies a tension to the first narrow strip of flexible material causing it to stretch and break if the first narrow strip breaks, the remaining end of the strip must be manually fed into the inlet of the injection molding machine. If the wide strip of rubber is stacked prior to being cut, the stacks must be neat to assure that when cut, the narrow strips will have a relatively uniform width. If the rubber is sloppily stacked, cutting the stack at various points will result in narrow strips with their widths varying along their length. A single strip could have a width of one inch at one point and a width of ten inches at another point. As a result, the narrow strip may easily break when being drawn into the injection molding machine or the strip may be too wide to properly fit into the inlet of the injection molding machine. In either case, manual labor may be required to either feed the remaining end of the narrow strip into the injection molding machine or to trim the narrow strip down to a size that the injection molding machine can utilize.
Currently, after exiting the calender, the wide strip of rubber is either placed on a festoon type conveyor or cut into narrow strips, and the narrow strips placed on the festoon type conveyor. On the festoon conveyor, each strip is hung over a series of bars and allowed to suspend loosely between the bars. The festoon conveyor carries the respective strip or strips of rubber through a cooling chamber where the rubber is cooled. After leaving the cooling chamber on the festoon conveyor, a belt conveyor removes the respective strip or strips from the festoon conveyor. The belt conveyor moves the respective strip or strips to a wigwag device for stacking.
The wigwag device is a simple mechanical device having a surface that moves back and forth at a constant speed to stack a respective strip into folded members. The stack created by the wigwag device is very messy. This is especially true when the wigwag is attempting to stack multiple narrow strips at one time because the narrow strips can easily overlap one another. Additionally, the wigwag device does not assure that each folded member of a respective strip is flatly placed on top of the previous folded member of that strip. When the respective folded members are not lying flatly, there is a greater likelihood that overlapping of the respective strips will result.
U.S. Pat. No. 3,032,337 entitled xe2x80x9cCONTINUOUS STACKING SYSTEMxe2x80x9d discloses a system to stack a continuous ribbon of material. This system positions a belt conveyor directly above the slab where the ribbon is to be stacked. An oscillating wall is used to help lay down the first portion of the ribbon and the remaining portions of the ribbon are placed by the side to side motion of the ribbon that results from the oscillating wall laying down the first ribbon.
This invention discloses a method of converting at least one strip of flexible material into at least one stack of folded members. The method includes the step of conveying a number of festoons formed from a strip of flexible material. The method is characterized by the step of depositing the respective festoons into a stack of folded members.
The step of depositing the respective festoons into a stack of folded members can be characterized further by the steps of: (i) laying an initial flap of flexible material on a stacking surface; (ii) creating a first folded member by placing a first festoon on the initial flap of flexible material; and creating additional folded members by placing each festoon upon a preceding festoon.
The method of this invention results in a stack having at least one side where the folded members are aligned. A further aspect of this invention provides additional steps that can be utilized to align additional sides of the stack.